As insects, honey bees are one of the major non-target species affected by a number of substances, collectively called “pesticides.” This generic term seeks to bring all the “killing” substances or “cides” under one big umbrella, which includes insecticides, fungicides, herbicides, among a raft of others.
The first pesticides found to be damaging to honey bees were those being applied to agricultural crops, usually as dusts, such as mercury and arsenic. This were broad spectrum and extremely dangerous. Subsequent research has developed a number of types of pesticides, which are more targeted to certain organisms. Thus, insecticides as a class were born. Again, honey bees were generally at great risk from these, so regulatory agencies attempted to minimize exposure through regulations.
The most important and effective rules have used the words, “do not apply when honey bees are present and/or plants are in bloom.” This is prominently displayed on many insecticides via the product label which is developed by the Environmental Protection Agency (EPA) for each registered pesticide. The “label is the law” has become the mantra for most pesticide applications, including those used by beekeepers themselves.
As a result of severe losses of honey bees across the United States, Congress passed the Beekeeper Indemnification Payment Program in 1970. This reimbursed beekeepers for pesticide losses and was retroactive to 1967. The program lasted only 10 years and was abandoned because it did nothing to solve the basic problem. Rumor also had it that beekeepers abused the program.The introduction of Penncap-M®, a microencapsulated insectide, caused the beekeepers further difficulty in the 1970s, but by then there was better labeling and stronger legislation from the Environmental Protection Agency.
Over the years, research has developed a number of classes of insecticides based on their chemical structure. Major types include pyrethrins (pyrethroids), carbamates, organophosphates, organochlorides and the current new class, neonicotinoids. There is a huge debate in beekeeping circles about the latter, which is considered relatively safe for mammals (e.g. humans), but usually much more toxic for insects. Recent discussion of the “neonics” have centered around their possible correlation with recent honey bee losses, often called “colony collapse disorder.” Adding complexity and uncertainty to pesticide effects is the possibility of several being applied at once in what is called a “tank mix.” For an expanded history of the above discussion, see the author’s reflections in 2007 as Colony Collapse Disorder (CCD) first became a beekeeping issue:
If one suspects honey bees are being affected by pesticides and there is visible evidence of loss, then an objective official (bee inspector) should be located to take a representative sample for analysis. Toxicity of pesticides is usually measured in the laboratory using something called the LD50 level, the amount of material needed to kill 50 percent of a relevant population, a relative toxicity.
Recent discussion concerning points of view by many of the entities manufacturing, regulating, researching and using pesticides have been less-than-helpful concerning effects of pesticides on honey bees. The question of whether pesticides kill bees or not is currently under investigation.
Since the arrival of Varroa, beekeepers themselves have begun using pesticides. Unfortunately many of these have an affinity for beeswax, which means bees are often at risk being poisoned by their own nest. In addition, non-lethal effects of chemical controls have also been observed in registered treatments.
The concept of synergy when is important when looking at how chemicals affect honey bees. This is described in some detail through a recent video that provides basic information on this subject.
Environmental contamination of honey bees and their colonies is also an issue that can arise. Several studies have shown these insects are like “flying dust mops,” that collect all kinds of dust and fly through clouds of other pollutants.
